1. Field of the Invention
The invention relates to a protection device, and more particularly to an electrostatic discharge (ESD) protection device.
2. Description of the Related Art
As the semiconductor manufacturing process develops, electrostatic discharge (ESD) protection becomes one of the most critical reliability issues for integrated circuits (IC). In particular, as the semiconductor process advances into the deep sub-micron stage, scaled-down devices and thinner gate oxides become more vulnerable to ESD stress.
Generally, the input/output pads on IC chips must at least sustain 2 kVolt of ESD stress of a high Human Body Mode (HBM) or 200V of ESD stress of a Machine Mode. Thus, the input/output pads on IC chips usually include ESD protect devices or circuits protecting the core circuit from ESD damage.